• Applied Chemistry for Engineering
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• v.28 no.4
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• pp.427-431
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• 2017

Recently, complaints of floor noise have been growing up with the rapid increase of the residential buildings. This demands the effective floor noise isolation system. Since the construction of high-rise the residential buildings will be increased even more in future, the noise isolation is a more important technology in the market. In this study, a new floor noise isolation panel (FNIP) was designed and manufactured using waste rubbers. The noise isolation was investigated at both laboratory and field conditions. Light and heavy weight shock wave showed 52 dB and 48 dB in the field test, respectively. The new system could reduce the total floor thickness by 22~42 mm.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.2
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• pp.115-122
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• 2012

Sound packages and damping materials have been widely applied on the floor to decrease the interior noise of a vehicle. Based on the previous researches on the low-noise vehicles, weight optimization through minimization of damping material usage is required while decreasing mid and high frequency range noise by application of sound packages. This paper describes the analysis process of robust design of vehicle body structure before applying damping materials and focuses on the analysis and test process of the location optimization at the stage of damping material application. A vibration experiment for the analysis of floor panel velocity with respect to the excitation of suspension attachment parts at the underfloor of a vehicle is performed. And through the improvement correlation between FEA and TEST, a design guide to optimize damping materials application in the early design stage is proposed. A research on vibration damping steel sheets and liquid acoustic spray on deadener(LASD) is performed to minimize manufacturing time and to minimize the space for pre-existing asphalt damping materials. As results of this study, panel stiffness is achieved through curved surface panel and bead optimization. And test baseline of optimum design is suggested through damping material optimization. And finally, through re-establishing the analysis process for vibration reduction of vehicle floors and lightweight design of damping materials, it is possible to design damping materials efficiently in the preceding stage of design.

• The Journal of the Acoustical Society of Korea
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• v.37 no.5
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• pp.323-330
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• 2018

This study investigated effects of absorbent gypsum board in the ceiling on low-frequency heavyweight floor impact sound through sound absorption coefficient and floor impact sound measurement. The sound absorption coefficients were measured with sound absorbent gypsum board, glass wool on gypsum board, and a double panel absorbent gypsum board (absorbent gypsum board + glass wool + absorbent gypsum board). Result showed that the absorbent gypsum board had sound absorption coefficient of 0.1 ~ 0.7 from 200 and 630 Hz octave band. The sound absorption coefficient was increased in all frequency range by adding glass wool. Additional absorbent gypsum board increased sound absorption coefficient up to 250 Hz octave band, but decreased over 250 Hz. Heavyweight floor impact sounds were measured in test building for three materials above, gypsum board, and bare slab. Result showed that glass wool on gypsum board and a double panel absorbent gypsum board reduced by 3 dB ~ 4 dB (single number quantity) heavyweight floor impact sound. Comparing with bare slab condition, floor impact sound reduction was mainly found from 125 Hz to 500 Hz octave band, and the maximum reduction was shown in the 250 Hz octave band.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.04a
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• pp.148-153
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• 1993

The paper presents the results of shaking table test conducted on the 1/3.3 scaled large concrete panel model. The behaviors of large concrete panel structures subjected to seismic excitations are controlled by capacity of horizontal and vertical joints. To Study the seismic capacity of the large concrete panel structures, experimental researches for joints and structural assemblage are needed. Especially, since the magnitude of seismic loads are depended on the variation of time, period and accelerations, dynamic test is needed for estimating the seismic resistance of large concrete panel structures. The objective of this paper is to study the behaviors of large concrete panel structures on seismic excitations and to estimate the safety. Test results are as follows : 1) Test model was critically damaged in the first floor horizontal joint by rocking. 2) Elastic limit(0.12kg) of test model was 5times higher than that of korean seismic design code. 3) Maxium base shear of test model at the ground acceleration of 0.12g was 3.5 times higher than the result of equivalent static analysis. 4) Damping ratio of test model turned out 3.9~5.3% and the period at 0.12g was 0.065sec.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.10a
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• pp.343-349
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• 1994

The purpose of this study is to investigate the mechanical properties of floor slab structures with high-strength and lightweight CFRC panel using fly ash, PAN-derived and Pitch-derived carbon fiber. As a result, the flexural strength of CFRC is remarkably increased by CF contents, but compressive strength of the CFRC is not so increased as flexural strength. The bulk specific gravity is influenced by FA contents more than by CF contents, The compressive strength and the flexural strength are increased by FA contests, but decreased the case of 30% of contents. In order to increasing the flexural-carrying capacity of floor slab structures, it is recommended that the shape of anchor for reinforcement is required type-C and the spacing of anchor is required below 60mm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.849-854
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• 2001

Cabin noise reduction in maglev trains developed by KIMM is studied. Based on the measurements of cabin noise and acceleration levels during running and zero speed conditions, dominant noise sources are identified. After spectra characteristics of noise sources is investigated, efficient noise reducing methods are studied such as STL increasement of floor panels, sealing, and absorption treatment. It is found that the most important noise sources are VVVF inverter and SLIM in running condition. Since the noise sources are under the cabin floor, complete sealing and high STL of the floor panel are shown to be the most crucial factors in noise reduction. After polyurethan form (50t) is added for more sound absorption and sealing treatment, the cabin noise is reduced by 3-4 ㏈.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.973-978
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• 2009

In this study, the thermal environment characteristics of On-Off control and thermal difference proportional control method in floor radiant heating system were researched by computer simulation. For the analysis of unsteady heat transfer phenomena in household, the method of using electrical equivalent R-C circuit is applied, and radiation heat transfer between panel, ceiling and walls in household is calculated by enclosure analysis method. The parametric study on two control methods, conventional on-off control and temperature error based time control(T.E.B.T.C.) method, are performed to compare thermal heating control performances, respectively.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.381-386
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• 2008

In this study, the energy characteristic of automatic thermostatic valves according to each heating method in floor radiant heating system were researched by computer simulation. For the analysis of unsteady heat transfer phenomena in household, the method of using electrical equivalent R-C circuit is applied, and radiation heat transfer between panel, ceiling and walls in household is calculated by enclosure analysis method. The parametric study on heating method, valve's control method, outdoor air condition, supply heating water temperature, supply flow rate are performed to compare energy characteristic, respectively.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.707-708
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• 2011

• Proceedings of the SAREK Conference
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• 2004.06a
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• pp.212-212
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• 2004